Abstract: Employees #1 and #2, volunteer fire fighters, were responding to a grass fire. Employee #1 was driving a water tanker, Employee #2 was the passenger. As they proceeded to the fire site, both employees indicated that they could feel the water in the tank sloshing, which caused the vehicle to sway and swerve, then roll over several times. Employee #2 was pinned by his ankles under the vehicle's cab and door. He was hospitalized with a broken pelvis. Employee #1 was admitted to the hospital for observation only and released. Neither employee was wearing a seat belt. The tanker truck had baffles only to prevent the water from sloshing from back to front, not from side to side. It could not be determined if the tanker was full, because the water in the tanker drained out during the accident.